Investigation, development, and application of inverse electron demand Diels-Alder reactions of heterocyclic dienes: A critical evaluation of the mode of cycloadditon, a probe for the question of concerted versus dipolar 4 + 2 cycloaddition, a determination of factors governing or influencing regioselectivity, the implementation of general and dependable synthetic procedures and the demonstration of the synthetic power of such processes for the simplification of contemporary synthetic challenges is presented in the context of a simple two-step construction of the entire carbon framework of streptonigrin and avendamycin, potent antitumor-antibiotics.